When God instituted the Covenant of the Law (the Law of Moses), he set aside one tribe from the twelve to serve him as attendants. This was the tribe of Levi. Unlike the other 11 tribes, they were given no inheritance in the promised land. Instead, their inheritance was the Tithes given by the other tribes. The Levites were chosen to be attendants and servants at the Tabernacle (and later the Temple). The family of Aaron were a member of the tribe of Levi, but God chose their line specifically to serve him as priests. They were the mediators between God and the Israelites. They were responsible for the sacrifices, as well as other priestly duties such as using the Urim and Thummim (lot-casting objects), and deciding the cleanliness or uncleanliness of disease victims. It was the high priest, and only he, who could go into the 'Holy of Holies' on the day of Atonement, in order to sprinkle the blood of the sacrificial bull on the mercy seat of the Ark of the Covenant. This symbolised the covering of the nation's sins. Nobody but a direct descendant of Aaron's family line could serve as a priest. The Levites were basically temple servants.